Desulfurization and novel sorbent for same

ABSTRACT

A sorbent composition comprising a support, a promoter, and a silicate can be used to desulfurize a hydrocarbon-containing fluid such as cracked-gasoline or diesel fuel.

This application is a continuation of application Ser. No. 10/021,982,filed Nov. 28, 2001, now pending.

BACKGROUND OF THE INVENTION

This invention relates to a sorbent composition, a process of making asorbent composition, and a process of using a sorbent composition forthe removal of sulfur from a hydrocarbon-containing fluid.

Hydrocarbon-containing fluids such as gasoline and diesel fuelstypically contain a quantity of sulfur. High levels of sulfur in suchautomotive fuels is undesirable because oxides of sulfur present inautomotive exhaust may irreversibly poison noble metal catalystsemployed in automobile catalytic converters. Emissions from suchpoisoned catalytic converters may contain high levels of non-combustedhydrocarbons, oxides of nitrogen, and/or carbon monoxide, which, whencatalyzed by sunlight, form ground level ozone, more commonly referredto as smog.

Much of the sulfur present in the final blend of most gasolinesoriginates from a gasoline blending component commonly known as“cracked-gasoline.” Thus, reduction of sulfur levels in cracked-gasolinewill inherently serve to reduce sulfur levels in most gasolines, suchas, automobile gasolines, racing gasolines, aviation gasolines, boatgasolines, and the like.

Many conventional processes exist for removing sulfur fromcracked-gasoline. However, most conventional sulfur removal processes,such as hydrodesulfurization, tend to saturate olefins and aromatics inthe cracked-gasoline and thereby reduce its octane number (both researchand motor octane number). Thus, there is a need for a process whereindesulfurization of cracked-gasoline is achieved while the octane numberis maintained.

In addition to the need for removing sulfur from cracked-gasoline, thereis also a need to reduce the sulfur content in diesel fuel. In removingsulfur from diesel fuel by hydrodesulfurization, the cetane is improvedbut there is a large cost in hydrogen consumption. Such hydrogen isconsumed by both hydrodesulfurization and aromatic hydrogenationreactions. Thus, there is a need for a process wherein desulfurizationis achieved without a significant consumption of hydrogen so as toprovide a more economical process for the desulfurization ofhydrocarbon-containing fluids.

Traditionally, sorbent compositions used in processes for the removal ofsulfur from hydrocarbon-containing fluids have been agglomeratesutilized in fixed bed applications. Because fluidized bed reactors haveadvantages over fixed bed reactors such as better heat transfer andbetter pressure drop, hydrocarbon-containing fluids are sometimesprocessed in fluidized bed reactors. Fluidized bed reactors generallyuse sorbents that are in the form of relatively small particulates. Thesize of these particulates is generally in the range of from about 1micrometer to about 1000 micrometers. However, conventional sorbentsgenerally do not have sufficient attrition resistance (i.e., resistanceto physical deterioration) for all applications. Consequently, finding asorbent with sufficient attrition resistance that removes sulfur fromthese hydrocarbon-containing fluids and that can be used in fluidized,transport, moving, or fixed bed reactors is desirable and would be ofsignificant contribution to the art and to the economy.

SUMMARY OF THE INVENTION

It is thus an object of the present invention to provide a novel sorbentsystem for the removal of sulfur from hydrocarbon-containing fluidstreams such as cracked-gasoline and diesel fuels.

Another object of the present invention is to provide a novel sorbentcomposition having an enhanced attrition resistance.

Yet another object of this invention is to provide a method of making anovel sorbent which is useful in the desulfurization of suchhydrocarbon-containing fluid streams.

Still another object of this invention is to provide a process for theremoval of sulfur-containing compounds from hydrocarbon-containing fluidstreams which minimizes saturation of olefins and aromatics therein.

A further object of this invention is to provide a process for theremoval of sulfur-containing compounds from hydrocarbon-containing fluidstreams which minimizes hydrogen consumption.

It should be noted that the above-listed objects need not all beaccomplished by the invention claimed herein and other objects andadvantages of this invention will be apparent from the followingdescription of the invention and appended claims.

In one aspect of the present invention, there is provided a novelsorbent composition suitable for removing sulfur from ahydrocarbon-containing fluid. The sorbent composition comprises asupport, a promoter, and a silicate.

In accordance with another aspect of the present invention, there isprovided a process of making a sorbent composition. The processcomprises: admixing a first support component and a second supportcomponent to form a support mix; particulating the support mix tothereby provide a support particulate; contacting the supportparticulate with a promoter to thereby provide a promoted particulatecomprising an unreduced promoter; reducing the promoted particulate toprovide a reduced sorbent composition comprising a reduced-valencepromoter; and incorporating a silicate with a silicate-enhancedcomponent selected from the group consisting of the support mix, thesupport particulate, the promoted particulate, and combinations thereof.

In accordance with a further aspect of the present invention, there isprovided a process for removing sulfur from a hydrocarbon-containingfluid stream. The process comprises the steps of: contacting thehydrocarbon-containing fluid stream with a sorbent compositioncomprising a support, a promoter, and a silicate in a desulfurizationzone under conditions such that there is formed a desulfurized fluidstream and a sulfurized sorbent; separating the desulfurized fluidstream from the sulfurized sorbent; regenerating at least a portion ofthe separated sulfurized sorbent in a regeneration zone so as to removeat least a portion of the sulfur therefrom and provide a desulfurizedsorbent; reducing the desulfurized sorbent in an activation zone toprovide a reduced sorbent composition which will affect the removal ofsulfur from the hydrocarbon-containing fluid stream when contacted withthe same; and returning at least a portion of the reduced sorbentcomposition to the desulfurization zone.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with a first embodiment of the present invention, a novelsorbent composition suitable for removing sulfur fromhydrocarbon-containing fluids is provided. The sorbent compositioncomprises a support, a promoter, and a silicate.

The support may be any component or combination of components which canbe used as a support for the sorbent composition of the presentinvention to help promote the desulfurization process of the presentinvention. Preferably, the support is an active component of the sorbentcomposition. Examples of suitable support components include, but arenot limited to, zinc oxide and any suitable inorganic and/or organiccarriers. Examples of suitable inorganic carriers include, but are notlimited to, silica, silica gel, alumina, diatomaceous earth, expandedperlite, kieselguhr, silica-alumina, titania, zirconia, zinc aluminate,zinc titanate, zinc silicate, magnesium aluminate, magnesium titanate,synthetic zeolites, natural zeolites, and combinations thereof. Examplesof suitable organic carriers include, but are not limited to, activatedcarbon, coke, charcoal, carbon-containing molecular sieves, andcombinations thereof. A preferred support comprises zinc oxide, silica,and alumina.

When the support comprises zinc oxide, the zinc oxide used in thepreparation of the sorbent composition of the present invention can beeither in a form of zinc oxide, such as powdered zinc oxide, or in theform of one or more zinc compounds that are convertible to zinc oxideunder the conditions of preparation described herein. Examples ofsuitable zinc compounds include, but are not limited to, zinc sulfide,zinc sulfate, zinc hydroxide, zinc carbonate, zinc acetate, zincnitrate, and combinations thereof. Preferably, the zinc oxide is in theform of powdered zinc oxide. When the support comprises zinc oxide, thezinc oxide will generally be present in the sorbent composition of thepresent invention in an amount in the range of from about 10 to about 90weight percent zinc oxide based on the total weight of the sorbentcomposition, preferably in an amount in the range of from about 15 toabout 60 weight percent zinc oxide, and most preferably in an amount inthe range of from 20 to 55 weight percent zinc oxide.

When the support comprises silica, the silica used in the preparation ofthe sorbent composition of the present invention can be either in theform of silica or in the form of one or more silicon compounds. Anysuitable type of silica may be employed in preparing the sorbentcomposition of the present invention. Examples of suitable types ofsilica include, but are not limited to, diatomite, expanded perlite,silicalite, silica colloid, flame-hydrolyzed silica, hydrolyzed silica,silica gel, precipitated silica, and combinations thereof. In addition,silicon compounds that are convertible to silica such as silicic acid,ammonium silicate and the like and combinations thereof can also beemployed. Preferably, the silica is in the form of diatomite or expandedperlite. When the support comprises silica, the silica will generally bepresent in the sorbent composition of the present invention in an amountin the range of from about 5 to about 85 weight percent silica based onthe total weight of the sorbent composition, preferably in an amount inthe range of from about 10 to about 60 weight percent silica, and mostpreferably in an amount in the range of from about 15 to 55 weightpercent silica.

When the support comprises alumina, the alumina used in preparing thesorbent composition of the present invention can be present in thesource of silica, can be any suitable commercially available aluminamaterial (including, but not limited to, colloidal alumina solutions,hydrated aluminas, and, generally, those alumina compounds produced bythe dehydration of alumina hydrates), or both. The preferred alumina isa hydrated alumina such as, for example, boehmite or pseudoboehmite.When the support comprises alumina, the alumina will generally bepresent in the sorbent composition of the present invention in an amountin the range of from about 1 to about 30 weight percent alumina based onthe total weight of the sorbent composition, preferably in an amount inthe range of from about 5 to about 20 weight percent alumina, and mostpreferably in an amount in the range of from 5 to 15 weight percentalumina.

The promoter can be any component which can be added to the sorbentcomposition of the present invention to help promote the desulfurizationprocess. The promoter is preferably a metal or metal oxide. As usedherein, the term “metal” denotes metal in any form such as elementalmetal or a metal-containing compound. As used herein, the term “metaloxide” denotes metal oxide in any form such as a metal oxide or a metaloxide precursor.

The metal or metal component of the metal oxide is preferably selectedfrom the group consisting of nickel, cobalt, iron, manganese, copper,zinc, molybdenum, tungsten, silver, tin, vanadium, antimony, andcombinations thereof. More preferably, the metal or metal component ofthe metal oxide is selected from the group consisting of nickel, cobalt,and combinations thereof. Most preferably, the promoter comprises nickelor nickel oxide. In a preferred method of making the present invention,the sorbent composition is promoted with a precursor of nickel oxidesuch as nickel nitrate, more preferably nickel nitrate hexahydrate.

A portion, preferably a substantial portion, of the promoter present inthe final sorbent composition is present in a reduced-valence state.Such reduced-valence promoter preferably has a valence which is lessthan that of the promoter in its common oxidized state, more preferablyless than 2, most preferably zero.

The promoter will generally be present in the sorbent composition of thepresent invention in an amount in the range of from about 1 to about 60weight percent promoter based on the total weight of the sorbentcomposition, preferably in an amount in the range of from about 5 toabout 50 weight percent promoter and, most preferably in an amount inthe range of from 10 to 40 weight percent promoter.

Of the total quantity of the promoter present in the sorbentcomposition, it is preferred that at least 10 weight percent of thepromoter is present as a reduced-valence promoter, more preferably atleast 40 weight percent of the promoter is a reduced-valence promoter,and most preferably at least 80 weight percent of the promoter is areduced-valence promoter.

The reduced-valence promoter will generally be present in the sorbentcomposition of the present invention in an amount in the range of fromabout 0.5 to about 50 weight percent reduced-valence promoter based onthe total weight of the sorbent composition, preferably in an amount inthe range of from about 4 to about 40 weight percent reduced-valencepromoter, and most preferably in an amount in the range of from 4 to 35weight percent reduced-valence promoter.

The silicate present in the composition of the present invention can beany silicate which can be added to a sorbent composition to enhance theattrition resistance of the sorbent composition. As used herein, theterm “attrition resistance” is a measure of a particle's resistance tosize reduction under controlled conditions of turbulent motion. Theattrition resistance of a particle can be quantified using the DavisonIndex. The Davison Index represents the weight percent of the over 20micrometer particle size fraction which is reduced to particle sizes ofless than 20 micrometers under test conditions. The Davison Index ismeasured using a Jet cup attrition determination method. The Jet cupattrition determination method involves screening a 5 gram sample ofsorbent to remove particles in the 0 to 20 micrometer size range. Theparticles above 20 micrometers are then subjected to a tangential jet ofair at a rate of 21 liters per minute introduced through a 0.0625 inchorifice fixed at the bottom of a specially designed Jet cup (1″ I.D.×2″height) for a period of 1 hour. The Davison Index (DI) is calculated asfollows:${DI} = {\frac{{{Wt}.\quad{of}}\quad 0{–20}\quad{Micrometer}\quad{Formed}\quad{During}\quad{Test}}{{{{Wt}.\quad{of}}\quad{Original}} + {20\quad{Micrometer}\quad{Fraction}\quad{Being}\quad{Tested}}} \times 100 \times {Correction}\quad{Factor}}$The correction factor (presently 0.3) is determined by using a knowncalibration standard to adjust for differences in Jet cup dimensions andwear.

The sorbent composition of the present invention preferably has aDavison Index of less than about 35 percent. More preferably, thesorbent composition of the present invention has a Davison Index of lessthan about 20 percent. Most preferably, the sorbent composition of thepresent invention has a Davison Index of less than 10 percent. A sorbentcomposition of the present invention, having a silicate incorporatedtherewith, has an enhanced attrition resistance when compared to sorbentcompositions which do not include a silicate.

The silicate employed in the present invention can be any compoundcomprising silicon, oxygen, and one or more metals with or withouthydrogen. The metal or metals of the silicate are preferably selectedfrom the group consisting of sodium, potassium, zirconium, aluminum,barium, beryllium, calcium, iron, magnesium, manganese, and combinationsthereof. Most preferably, the silicate is sodium silicate.

The silicate will generally be present in the sorbent composition of thepresent invention in an attrition-resistance-enhancing amount which iseffective to enhance attrition resistance compared to a sorbentcomposition which does not have the silicate. The silicate willgenerally be present in the sorbent composition of the present inventionin an amount in the range of from about 1 to about 40 weight percentsilicate based on the total weight of the sorbent composition,preferably in an amount in the range of from about 5 to about 30 weightpercent silicate, and more preferably in an amount in the range of from10 to 20 weight percent silicate.

The sorbent composition of the present invention can additionallycomprise a binder component. The binder can be any suitable compoundthat has cement-like properties which can help to bind the particulatecomposition together. Suitable examples of such binders include, but arenot limited to, cements such as, for example, gypsum plaster, commonlime, hydraulic lime, natural cements, portland cements, and highalumina cements, and the like and combinations thereof. A particularlypreferred binder is calcium aluminate. When a binder is present, theamount of binder in the sorbent composition of the present invention isgenerally in the range of from about 0.1 weight percent binder to about50 weight percent binder. Preferably, the amount of binder in a sorbentcomposition of the present invention is in the range of from about 1weight percent to about 40 weight percent and, more preferably in therange of 5 weight percent to 30 weight percent.

In accordance with a second embodiment of the present invention, aprocess for making the inventive sorbent composition of the firstembodiment of the present invention is provided.

In the manufacture of the sorbent composition of the present invention,the support is generally prepared by combining a first supportcomponent, such as zinc oxide, and second support component, such as acarrier, by any suitable method or manner which provides for theintimate mixing of such components to thereby provide a substantiallyhomogeneous mixture comprising the support components, preferably asubstantially homogeneous mixture comprising zinc oxide and a carrier,most preferably a homogeneous mixture comprising zinc oxide, silica, andalumina. Any suitable means for mixing the support component can be usedto achieve the desired dispersion of the components. Examples ofsuitable means for mixing include, but are not limited to, mixingtumblers, stationary shells or troughs, Muller mixers, which are of thebatch or continuous type, impact mixers, and the like. It is presentlypreferred to use a Muller mixer as the means for mixing the supportcomponents.

The support ingredients are admixed by any manner known in the art toprovide a support mix which can be in the form selected from the groupconsisting of a wet mix, a dough, a paste, a slurry, and the like. Suchresulting support mix can then be shaped to form a particulate(s)selected from the group consisting of a granulate, an extrudate, atablet, a sphere, a pellet, a micro-sphere, and the like. For example,if the resulting support mixture is in the form of a wet mix, the wetmix can be densified, dried, calcined, and thereafter shaped, orparticulated, through the granulation of the densified, dried, calcinedmix to form granulates. Also for example, when the resulting support mixis in the form of either a dough state or paste state, such resultingmixture can then be shaped, preferably extruded, to form a particulate,preferably cylindrical extrudates having a diameter in the range of fromabout 1/32 inch to ½ inch and any suitable length, preferably a lengthin the range of from about ⅛ inch to about 1 inch. The resulting supportparticulates, preferably cylindrical extrudates, are then dried andcalcined under conditions as disclosed herein.

More preferably, the support mix is in the form of a slurry and theparticulation of such slurry is achieved by spray drying the slurry toform micro-spheres thereof having a mean particle size generally in therange of from about 1 micrometer to about 500 micrometers, preferably inthe range of from about 10 micrometers to about 300 micrometers. Spraydrying is known in the art and is discussed in Perry's ChemicalEngineers' Handbook, Sixth Edition, published by McGraw-Hill, Inc., atpages 20-54 through 20-58. Additional information can be obtained fromthe Handbook of Industrial Drying, published by Marcel Dekker. Inc., atpages 243 through 293. As used herein, the term “mean particle size”refers to the size of the particulate material as determined by using aRO-TAP Testing Sieve Shaker, manufactured by W.S. Tyler Inc., of Mentor,Ohio, or other comparable sieves. The material to be measured is placedin the top of a nest of standard eight inch diameter stainless steelframed sieves with a pan on the bottom. The material undergoes siftingfor a period of about 10 minutes; thereafter, the material retained oneach sieve is weighed. The percent retained on each sieve is calculatedby dividing the weight of the material retained on a particular sieve bythe weight of the original sample. This information is used to computethe mean particle size.

When the particulation is achieved by preferably spray drying, adispersant can be utilized and can be any suitable compound that helpsto promote the spray drying ability of the resulting mixture which ispreferably in the form of a slurry which preferably comprises zincoxide, silica, and alumina. In particular, the dispersant is useful inpreventing deposition, precipitation, settling, agglomerating, adheringand caking of solid particles in a fluid medium. Examples of suitabledispersants include, but are not limited to, condensed phosphates,sulfonated polymers, ammonium polyacrylate, sodium polyacrylate,ammonium polymethacrylate, poly(methyl methacrylate), polyacrylic acid(sodium salt), polyacrylamide, and the like and combinations thereof.The term “condensed phosphates” refers to any dehydrated phosphate wherethe H₂O:P₂O₅ is less than about 3:1. Specific examples of suitabledispersants include, but are not limited to, sodium pyrophosphate,sodium metaphosphate, sulfonated styrene maleic anhydride polymer, andthe like and combinations thereof. The amount of the dispersant used isgenerally in the range of from about 0.01 weight percent to about 10weight percent dispersant based on the total weight of the support.Preferably, the amount of the dispersant used is in the range of fromabout 0.1 weight percent to about 8 weight percent and, more preferablythe amount of the dispersant used is in the range of from 1 weightpercent to 5 weight percent.

In preparing a preferred spray-dried sorbent composition of the presentinvention, an acid can be used. In general, the acid can be an organicacid or a mineral acid. If the acid is an organic acid, it is preferablya carboxylic acid. If the acid is a mineral acid it is preferably anitric acid, a phosphoric acid, hydrochloric acid, or a sulfuric acid.Mixtures of these acids can also be used. Generally, the acid is usedwith water to form a dilute aqueous acid solution. The amount of acid inthe aqueous acid solution is generally in the range of from about 0.01volume percent to about 20 volume percent based on the total volume ofthe acid solution. Preferably, the amount of acid is in the range offrom about 0.1 volume percent to about 15 volume percent, and morepreferably the amount of acid is in the range of from 1 volume percentto 10 volume percent. In general, the amount of acid to be used is basedon the amount of the dry components. That is, the ratio of all of thedry components (in grams) to the acid (in milliliters) should be lessthan about 1.75:1. However, it is preferred if this ratio is less thanabout 1.25:1 and it is more preferred if it is less than about 0.75:1.These ratios will help to form a mixture that is a liquid solution, aslurry, or a paste that is capable of being dispersed in a fluid-likespray.

The spray-dried support particulate can then be dried and calcined underdrying and calcining conditions disclosed herein, to form a dried andcalcined support particulate.

The resulting dried and calcined support particulate is then contactedwith the promoter to thereby incorporate the promoter with the dried andcalcined support particulate. The promoter may be incorporated in, on,or with the dried and calcined support particulate by any suitable meansor method known in the art such as, for example, impregnating, soaking,spraying, and combinations thereof. The preferred method ofincorporating the promoter into the dried and calcined supportparticulate is impregnating using standard incipient wetnessimpregnation techniques. A preferred method uses an impregnatingsolution comprising the desired concentration of the promoter so as toultimately provide a promoted particulate which can be subjected todrying, calcining, and reduction to provide the sorbent composition ofthe present invention. The impregnating solution can be any aqueoussolution in amounts of such solution which suitably provides for theimpregnation of the dried and calcined support particulates. A preferredimpregnating solution is formed by dissolving a promoter-containingcompound in water. It is acceptable to use somewhat of an acidicsolution to aid in the dissolution of the promoter-containing compound.It is more preferred for the support particulates to be impregnated withthe promoter by use of a solution containing nickel nitrate hexahydratedissolved in water.

Generally, the amount of the promoter incorporated, preferablyimpregnated, onto, into, or with the support component is an amountwhich provides, after the promoted particulate material has been driedcalcined, and reduced, a sorbent composition having an amount of thepromoter as disclosed herein. It may be necessary to employ more thanone incorporation step in order to obtain the desired quantity ofpromoter. If so, such additional incorporation(s) are performed in thesame manner described above.

Once the promoter has been incorporated in, on, or with the dried andcalcined support particulate, the promoted particulate is subsequentlydried and calcined under conditions disclose herein to thereby provide adried, calcined, promoted particulate comprising an unreduced promoter.

Generally, a drying condition, as referred to herein, can include atemperature in the range of from about 180° F. to about 290° F.,preferably in the range of from about 190° F. to about 280° F., and morepreferably in the range of from 200° F. to 270° F. Such drying conditioncan also include a time period generally in the range of from about 0.5hour to about 60 hours, preferably in the range of from about 1 hour toabout 40 hours, and more preferably in the range of from 1.5 hours to 20hours. Such drying condition can also include a pressure generally inthe range of from about atmospheric (i.e., about 14.7 pounds per squareinch absolute) to about 150 pounds per square inch absolute (psia),preferably in the range of from about atmospheric to about 100 psia,more preferably about atmospheric, so long as the desired temperaturecan be maintained. Any drying method(s) known to one skilled in the artsuch as, for example, air drying, heat drying, vacuum drying, and thelike and combinations thereof can be used.

Generally, a calcining condition, as referred to herein, can include atemperature in the range of from about 400° F. to about 1800° F.,preferably in the range of from about 600° F. to about 1600° F., andmore preferably in the range of from 800° F. to about 1500° F. Suchcalcining condition can also include a time period generally in therange of from about 1 hour to about 60 hours, preferably in the range offrom about 2 hours to about 20 hours, and more preferably in the rangeof from 3 hours to 15 hours. Such calcining condition can also include apressure, generally in the range of from about 7 pounds per square inchabsolute (psia) to about 750 psia, preferably in the range of from about7 psia to about 450 psia, and more preferably in the range of from 7psia to 150 psia.

The dried, calcined, promoted particulates are thereafter subjected toreduction with a suitable reducing agent, preferably hydrogen, underreducing conditions, to thereby provide a reduced sorbent compositioncomprising a reduced-valence promoter having a valence which is lessthan that of the unreduced promoter, preferably less than 2, mostpreferably zero. Reduction can be carried out at a temperature in therange of from about 100° F. to about 1500° F. and at a pressure in therange of from about 15 pounds per square inch absolute (psia) to about1,500 psia. Such reduction is carried out for a time period sufficientto achieve the desired level of reduction of the promoter. Suchreduction can generally be achieved in a time period in the range offrom about 0.01 hour to about 20 hours.

The silicate can be incorporated into the sorbent composition at avariety of stages during the above-described preparation of the sorbentcomposition and in a variety of manners. For example, the silicate canbe incorporated onto, into, or with the support mix, the unpromotedsupport particulate (before or after drying and calcining), the promotedparticulate (before or after drying and calcining), or combinationsthereof.

If the silicate is incorporated into the support mix, such incorporationis preferably accomplished by physically mixing the silicate with thesupport mix using any means known in art. Such mixing can beaccomplished in the same manner in which the components of the supportmix were combined. When the silicate is incorporated into the supportmix preferably, zinc oxide, alumina, silica, and the silicate are mixedtogether to provide a support slurry capable of particulation by spraydrying.

If the silicate is incorporated onto, into or with a particulate such asthe unpromoted support particulate (before or after drying andcalcining) or the promoted particulate (before or after drying andcalcining), such incorporation can be accomplished by any method knownin the art. It is presently preferred that the silicate incorporationalways be followed by at least one promoter incorporation prior toreduction. Suitable methods of contacting the particulate with thesilicate can include, but are not limited to, impregnating techniquessuch as standard incipient wetness impregnation (i.e., essentiallycompletely filling the pores of a substrate material with a solution ofthe incorporating elements), spray impregnation techniques, wetimpregnation, spray drying, chemical vapor deposition, plasma spraydeposition, melting impregnation, and the like. It is preferred,however, to use a spray impregnation technique whereby the particulateis contacted with a fine spray of a solution containing the silicatewherein the solution has the desired amount of the silicate dissolved ina sufficient volume of an aqueous medium, such as water, to fill thetotal pore volume of the particulate or, in other words, to effect anincipient wetness impregnation of the particulate. For example, sprayingof an aqueous solution containing silicate onto the sorbent material canbe conducted using a ultrasonic nozzle to atomize the aqueous solutionwhich can then be sprayed onto the particulate while such particulate isrotated on a disk or being tumbled in a tumbler.

The concentration of the silicate in the aqueous solution can generallybe in the range of from about 0.1 gram of silicate per gram of solutionto about 10 grams of silicate per gram of solution. Preferably, theconcentration of the silicate in the solution can be in the range offrom about 0.1 gram of silicate per gram of solution to about 5 grams ofsilicate per gram of solution and, more preferably, the concentration ofsilicate in the solution can be in the range of from 0.1 gram ofsilicate per gram of solution to 2 grams of silicate per gram ofsolution. Generally, the weight ratio of silicate to solution can be inthe range of from about 0.25:1 to about 2:1, preferably, in the range offrom about 0.5:1 to about 1.5:1 and, more preferably, in the range offrom 0.75:1 to 1.25:1.

After incorporation of the silicate on, in, or with the particulate, theattrition-resistance-enhanced particulate is preferably dried andcalcined under drying and calcining conditions disclosed herein.

In accordance with a third embodiment of the present invention, adesulfurization process is provided which employs the novel sorbentcomposition described herein.

The hydrocarbon-containing fluid feed employed in the desulfurizationprocess of this embodiment of the present invention is preferably asulfur-containing hydrocarbon fluid, more preferably, gasoline or dieselfuel, most preferably cracked-gasoline or diesel fuel.

The hydrocarbon-containing fluid described herein as suitable feed inthe process of the present invention comprises a quantity of olefins,aromatics, sulfur, as well as paraffins and naphthenes. The amount ofolefins in gaseous cracked-gasoline is generally in the range of fromabout 10 to about 35 weight percent olefins based on the total weight ofthe gaseous cracked-gasoline. For diesel fuel there is essentially noolefin content. The amount of aromatics in gaseous cracked-gasoline isgenerally in the range of from about 20 to about 40 weight percentaromatics based on the total weight of the gaseous cracked-gasoline. Theamount of aromatics in gaseous diesel fuel is generally in the range offrom about 10 to about 90 weight percent aromatics based on the totalweight of the gaseous diesel fuel. The amount of sulfur in thehydrocarbon-containing fluid, preferably cracked-gasoline or dieselfuel, suitable for use in a process of the present invention can be inthe range of from about 100 parts per million sulfur by weight of thecracked-gasoline to about 10,000 parts per million sulfur by weight ofthe cracked-gasoline and from about 100 parts per million sulfur byweight of the diesel fuel to about 50,000 parts per million sulfur byweight of the diesel fuel prior to the treatment of suchhydrocarbon-containing fluid with the process of the present invention.The amount of sulfur in the desulfurized hydrocarbon-containing fluidfollowing treatment in accordance with the process of the presentinvention is less than about 100 parts per million (ppm) sulfur byweight of hydrocarbon-containing fluid, preferably less than about 90ppm sulfur by weight of hydrocarbon-containing fluid, and morepreferably less than about 80 ppm sulfur by weight ofhydrocarbon-containing fluid.

As used herein, the term “gasoline” denotes a mixture of hydrocarbonsboiling in the range of from about 100° F. to about 400° F., or anyfraction thereof. Examples of suitable gasoline include, but are notlimited to, hydrocarbon streams in refineries such as naphtha,straight-run naphtha, coker naphtha, catalytic gasoline, visbreakernaphtha, alkylate, isomerate, reformate, and the like and combinationsthereof.

As used herein, the term “cracked-gasoline” denotes a mixture ofhydrocarbons boiling in the range of from about 100° F. to about 400°F., or any fraction thereof, that are products from either thermal orcatalytic processes that crack larger hydrocarbon molecules into smallermolecules. Examples of suitable thermal processes include, but are notlimited to, coking, thermal cracking, visbreaking and the like andcombinations thereof. Examples of suitable catalytic cracking processesinclude, but are not limited to fluid catalytic cracking, heavy oilcracking, and the like and combinations thereof. Thus, examples ofsuitable cracked-gasoline include, but are not limited to, cokergasoline, thermally cracked gasoline, visbreaker gasoline, fluidcatalytically cracked gasoline, heavy oil cracked gasoline, and the likeand combinations thereof. In some instances, the cracked-gasoline may befractionated and/or hydrotreated prior to desulfurization when used as ahydrocarbon-containing fluid in a process of the present invention.

As used herein, the term “diesel fuel” denotes a mixture of hydrocarbonsboiling in the range of from about 300° F. to about 750° F., or anyfraction thereof. Examples of suitable diesel fuels include, but are notlimited to, light cycle oil, kerosene, jet fuel, straight-run diesel,hydrotreated diesel, and the like and combinations thereof.

As used herein, the term “sulfur” denotes sulfur in any form such aselemental sulfur or a sulfur compound normally present in ahydrocarbon-containing fluid such as cracked gasoline or diesel fuel.Examples of sulfur which can be present during a process of the presentinvention, usually contained in a hydrocarbon-containing fluid, include,but are not limited to, hydrogen sulfide, carbonyl sulfide (COS), carbondisulfide (CS₂), mercaptans (RSH), organic sulfides (R—S—R), organicdisulfides (R—S—S—R), thiophene, substituted thiophenes, organictrisulfides, organic tetrasulfides, benzothiophene, alkyl thiophenes,alkyl benzothiophenes, alkyl dibenzothiophenes, and the like andcombinations thereof as well as the heavier molecular weights of samewhich are normally present in a diesel fuel of the types contemplatedfor use in a process of the present invention, wherein each R can be analkyl or cycloalkyl or aryl group containing one carbon atom to tencarbon atoms.

As used herein, the term “fluid” denotes gas, liquid, vapor, andcombinations thereof.

As used herein, the term “gaseous” denotes that state in which thehydrocarbon-containing fluid, such as cracked-gasoline or diesel fuel,is primarily in a gas or vapor phase.

The desulfurizing of the hydrocarbon-containing fluid is carried out ina desulfurization zone under a set of conditions that includes totalpressure, temperature, weight hourly space velocity, and hydrogen flow.These conditions are such that the sorbent composition can desulfurizethe hydrocarbon-containing fluid to produce a desulfurizedhydrocarbon-containing fluid and a sulfurized sorbent composition.

In desulfurizing the hydrocarbon-containing fluid, it is preferred thatthe hydrocarbon-containing fluid, preferably cracked-gasoline or dieselfuel, be in a gas or vapor phase. However, in the practice of thepresent invention it is not essential that the hydrocarbon-containingfluid be totally in a gas or vapor phase.

In desulfurizing the hydrocarbon-containing fluid, the total pressurecan be in the range of from about 15 pounds per square inch absolute(psia) to about 1500 psia. However, it is presently preferred that thetotal pressure be in a range of from about 50 psia to about 500 psia. Ingeneral, the temperature should be sufficient to keep thehydrocarbon-containing fluid in essentially a vapor or gas phase. Whilesuch temperatures can be in the range of from about 100° F. to about1000° F., it is presently preferred that the temperature be in the rangeof from about 400° F. to about 800° F. when treating a cracked-gasolineand in the range of from about 500° F. to about 900° F. when treating adiesel fuel.

Weight hourly space velocity (WHSV) is defined as the numerical ratio ofthe rate at which a hydrocarbon-containing fluid is charged to thedesulfurization zone in pounds per hour at standard condition oftemperature and pressure (STP) divided by the pounds of sorbentcomposition contained in the desulfurization zone to which thehydrocarbon-containing fluid is charged. In the practice of the presentinvention, such WHSV should be in the range of from about 0.5 hr⁻¹ toabout 50 hr⁻¹, preferably in the range of from about 1 hr⁻¹ to about 20hr⁻¹. The desulfurizing (i.e., desulfurization) of thehydrocarbon-containing fluid should be conducted for a time sufficientto affect the removal of at least a substantial portion sulfur from suchhydrocarbon-containing fluid.

In desulfurizing the hydrocarbon-containing fluid, it is presentlypreferred that an agent be employed which interferes with any possiblechemical or physical reacting of the olefinic and aromatic compounds inthe hydrocarbon-containing fluid which is being treated with a sorbentcomposition of the present invention. Preferably, such agent ishydrogen. Hydrogen flow in the desulfurization zone is generally suchthat the mole ratio of hydrogen to hydrocarbon-containing fluid is therange of from about 0.1 to about 10, preferably in the range of fromabout 0.2 to about 3.

If desired, during the desulfurizing of the hydrocarbon-containing fluidaccording to the process of the present invention, a diluent such asmethane, carbon dioxide, flue gas, nitrogen and the like andcombinations thereof can be used. Thus, it is not essential to thepractice of a process of the present invention that a high purityhydrogen be employed in achieving the desired desulfurization of ahydrocarbon-containing fluid such as cracked-gasoline or diesel fuel.

It is presently preferred, when the desulfurization zone is in afluidized bed reactor system, that a sorbent composition be used havinga mean particle size, as described herein, in the range of from about 1micrometer to about 500 micrometers. Preferably, such sorbentcomposition has a mean particle size in the range of from about 10micrometers to about 300 micrometers, most preferably, from about 10 toabout 100 micrometers. When a fixed bed reactor system is employed asthe desulfurization zone of the present invention, the sorbentcomposition should generally have a particulate size in the range offrom about 1/32 inch to about ½ inch diameter, preferably in the rangeof from about 1/32 inch to about ¼ inch diameter. It is furtherpresently preferred to use a sorbent composition having a surface areain the range of from about 1 square meter per gram to about 1000 squaremeters per gram (m²/g), preferably in the range of from about 1 m²/g toabout 800 m²/g.

After sulfur removal in the desulfurization zone, the desulfurizedhydrocarbon-containing fluid and sulfurized sorbent composition can thenbe separated by any manner or method known in the art that can separatea solid from a fluid, preferably a solid from a gas. Examples ofsuitable separating means for separating solids and gases include, butare not limited to, cyclonic devices, settling chambers, impingementdevices, filters, and combinations thereof. The desulfurizedhydrocarbon-containing fluid, preferably desulfurized gaseouscracked-gasoline or desulfurized gaseous diesel fuel, can then berecovered and preferably liquefied. Liquification of such desulfurizedhydrocarbon-containing fluid can be accomplished by any manner or methodknown in the art.

The sulfurized sorbent is then regenerated in a regeneration zone undera set of conditions that includes temperature, total pressure, andsulfur removing agent partial pressure. The regenerating is carried outat a temperature generally in the range of from about 100° F. to about1500° F., preferably in the range of from about 800° F. to about 1200°F. Total pressure is generally in the range of from about 25 pounds persquare inch absolute (psia) to about 500 psia. The sulfur removing agentpartial pressure is generally in the range of from about 1 percent toabout 100 percent of the total pressure.

The sulfur removing agent, i.e., regenerating agent, is a composition(s)that helps to generate gaseous sulfur-containing compounds andoxygen-containing compounds such as sulfur dioxide, as well as to burnoff any remaining hydrocarbon deposits that might be present. Thepreferred sulfur removing agent, i.e., regenerating agent, suitable foruse in the regeneration zone is oxygen or an oxygen-containing gas(es)such as air. Such regeneration is carried out for a time sufficient toachieve the desired level of regeneration. Such regeneration cangenerally be achieved in a time period in the range of from about 0.1hour to about 24 hours, preferably in the range of from about 0.5 hourto about 3 hours.

In carrying out the process of the present invention, a stripper zonecan be inserted before and/or after, preferably before, regenerating thesulfurized sorbent composition in the regeneration zone. Such stripperzone, preferably utilizing a stripping agent, will serve to remove aportion, preferably all, of any hydrocarbon(s) from the sulfurizedsorbent composition. Such stripper zone can also serve to remove oxygenand sulfur dioxide from the system prior to introduction of theregenerated sorbent composition into the activation zone. Such strippingemploys a set of conditions that includes total pressure, temperature,and stripping agent partial pressure.

Preferably, the stripping, when employed, is carried out at a totalpressure in the range of from about 25 pounds per square inch absolute(psia) to about 500 psia. The temperature for such stripping can be inthe range of from about 100° F. to about 1000° F. Such stripping iscarried out for a time sufficient to achieve the desired level ofstripping. Such stripping can generally be achieved in a time period inthe range of from about 0.1 hour to about 4 hours, preferably in therange of from about 0.3 hour to about 1 hour. The stripping agent is acomposition(s) that helps to remove a hydrocarbon(s) from the sulfurizedsorbent composition. Preferably, the stripping agent is nitrogen.

After regeneration, and optionally stripping, the desulfurized sorbentcomposition is then subjected to reducing, i.e., activating, in anactivation zone with a reducing agent, preferably hydrogen, so that atleast a portion of the unreduced promoter incorporated on, in, or withthe sorbent composition is reduced to thereby provide a reduced sorbentcomposition comprising a reduced-valence promoter. Such reduced-valencepromoter is incorporated on, in, or with such sorbent composition in anamount that provides for the removal of sulfur from thehydrocarbon-containing fluid according to a process of the presentinvention.

In general, when practicing a process of the present invention, thereducing, i.e., activating, of the desulfurized sorbent composition iscarried out at a temperature in the range of from about 100° F. to about1500° F. and at a pressure in the range of from about 15 pounds persquare inch absolute (psia) to about 1500 psia. Such reduction iscarried out for a time sufficient to achieve the desired level ofpromoter reduction. Such reduction can generally be achieved in a timeperiod in the range of from about 0.01 hour to about 20 hours.

Following the reducing, i.e., activating, of the regenerated,desulfurized sorbent composition, at least a portion of the resultingreduced (i.e., activated) sorbent composition can be returned to thedesulfurization zone.

When carrying out the desulfurization process of the present invention,the steps of desulfurizing, regenerating, reducing (i.e., activating),and optionally stripping before and/or after such regenerating, can beaccomplished in a single zone or vessel or in multiple zones or vessels.The desulfurization zone can be any zone wherein desulfurizing ahydrocarbon-containing fluid such as cracked-gasoline, diesel fuel orthe like can take place. The regeneration zone can be any zone whereinregenerating or desulfurizing a sulfurized sorbent composition can takeplace. The activation zone can be any zone wherein reducing, i.e.,activating, a regenerated, desulfurized sorbent composition can takeplace. Examples of suitable zones are fixed bed reactors, moving bedreactors, fluidized bed reactors, transport reactors, reactor vesselsand the like.

When carrying out the process of the present invention in a fixed bedreactor system, the steps of desulfurizing, regenerating, reducing, andoptionally stripping before and/or after such regenerating areaccomplished in a single zone or vessel. When carrying out the processof the present invention in a fluidized bed reactor system, the steps ofdesulfurizing, regenerating, reducing, and optionally stripping beforeand/or after such regenerating are accomplished in multiple zones orvessels.

When the desulfurized hydrocarbon-containing fluid resulting from thepractice of a process of the present invention is a desulfurizedcracked-gasoline, such desulfurized cracked-gasoline can be used in theformulation of gasoline blends to provide gasoline products suitable forcommercial consumption and can also be used where a cracked-gasolinecontaining low levels of sulfur is desired.

When the desulfurized hydrocarbon-containing fluid resulting from thepractice of a process of the present invention is a desulfurized dieselfuel, such desulfurized diesel fuel can be used in the formulation ofdiesel fuel blends to provide diesel fuel products suitable forcommercial consumption and can also be used where a diesel fuelcontaining low levels of sulfur is desired.

The following examples are presented to further illustrate thisinvention and are not to be construed as unduly limiting the scope ofthis invention. Mesh sieve numbers used in the Examples are U.S.Standard Sieve Series, ASTM Specification E-11-61.

EXAMPLE I

Sorbent A (control) was prepared by mixing 20 grams of sodiumpyrophosphate (available from Aldrich Chemical Company, Milwaukee, Wis.)and 2224 grams of distilled water in a Cowles dissolver to create asodium pyrophosphate solution. A 200 gram quantity of aluminum hydroxidepowder (Dispal® Alumina Powder, available from CONDEA Vista Company,Houston, Tex.), a 628 gram quantity of diatomaceous earth (Celite®Filter Cell, available from Manville Sales Corporation, Lampoc, Calif.),and a 788 gram quantity of zinc oxide powder (available from ZincCorporation, Monaca, Pa.) were then mixed to form a powdered mixture.The powdered mixture was slowly added to the sodium pyrophosphatesolution and mixed for 15 minutes to create a sorbent base slurry. Theresulting mixed slurry was sieved through a 25-mesh screen.

The sorbent base slurry was then formed into sorbent base particulateusing a counter-current spray drier (Niro Mobile Minor Spray Dryer,available from Niro Inc., Columbia, Md.). The sorbent base slurry wascharged to the spray drier wherein it was contacted in a particulatingchamber with air flowing through the chamber. The operating conditionsof the spray dryer included an inlet temperature of 320° C. and anoutlet temperature of about 100° C. to about 120° C. The sorbent baseparticulate was then dried in an oven by ramping the oven temperature at3° C./min to 150° C. and holding at 150° C. for 3 hours. The driedsorbent base particulate was then calcined by ramping the oventemperature at 3° C./min to 635° C. and holding at 635° C. for 1 hour.

The calcined sorbent base particulate was then sieved to provide a 100gram quantity which passed through the 50 mesh sieve but was retainedabove the 140 mesh sieve (i.e., −50/+140 mesh). The resulting 100 gramquantity of sieved sorbent base particulate was then impregnated with asolution containing 59.42 grams of nickel nitrate hexahydrate and 62.9grams of distilled water using incipient wetness techniques. Theimpregnated sorbent was then put in an oven and dried by ramping theoven temperature at 3° C./min to 150° C. and holding at 150° C. for 3hours. The dried sorbent was then calcined by ramping the oventemperature at 3° C./min to 635° C. and holding at 635° C. for 1 hour.The resulting nickel-promoted sorbent was designated Sorbent A.

Sorbent B (control) was prepared by impregnating a 50.0 gram quantity ofSorbent A with a solution containing 37.14 grams of nickel nitratehexahydrate and 7.45 grams of distilled water by spraying the solutionon the sorbent with an ultrasonic nozzle. The twice-impregnated sorbentwas then put in an oven and dried by ramping the oven temperature at 3°C./min to 150° C. and holding at 150° C. for 1 hour. The dried sorbentwas then calcined by ramping the over temperature at 5° C./min to 635°C. and holding at 635° C. for 1 hour. The resultingtwice-nickel-promoted sorbent was designated Sorbent B.

Sorbent C was prepared by mixing 20 grams of sodium pyrophosphate(available from Aldrich Chemical Company, Milwaukee, Wis.), 1690 gramsof dionized water, 200 grams of aluminum hydroxide powder (Dispal®Alumina Powder, available from CONDEA Vista Company, Houston, Tex.), 471grams of diatomaceous earth (Celite® Filter Cell, available fromManville Sales Corporation, Lampoc, Calif.), 788 grams of zinc oxidepowder (available from Zinc Corporation, Monaca, Pa.), and 870 grams ofa sodium silicate solution containing 9.1% Na₂O and 29.2% SiO₂(available from Brainerd Chemical Co., Tulsa, Okla.) to form a sorbentbase slurry.

The sorbent base slurry was then formed into sorbent base particulateusing a counter-current spray drier (Niro Mobile Minor Spray Dryer,available from Niro Inc., Columbia, Md.). The sorbent base slurry wascontacted in a particulating chamber with air flowing through thechamber. The air flowing through the particulating chamber had an inlettemperature of about 320° C. and an outlet temperature of about 145° C.The sorbent base particulate was then dried in an oven by ramping theoven temperature at 3° C./min to 150° C. and holding at 150° C. for 1hour. The dried sorbent base particulate was then calcined by rampingthe oven temperature at 5° C./min to 635° C. and holding at 635° C. for1 hour.

A 100 gram quantity of the calcined sorbent base particulate was thenimpregnated with a solution containing 74.28 grams of nickel nitratehexahydrate and 8 grams of distilled water by spraying the solution onthe particulate with an ultrasonic nozzle. The impregnated sorbent wasthen put in an oven and dried by ramping the oven temperature at 3°C./min to 635° C. and holding at 635° C. for 1 hour.

The dried sorbent was then calcined by ramping the oven temperature at3° C./min to 635° C. and holding at 635° C. for 1 hour.

The nickel-promoted sorbent was then sieved and 114.6 grams of thesorbent which passed through the 50 mesh sieve and was retained abovethe 325 mesh sieve was retained. The 114.6 gram quantity of the −50/+325nickel-promoted sorbent was then impregnated with a solution containing85.12 grams of nickel nitrate hexahydrate and 8 grams of distilled waterby spraying the solution on the sorbent with an ultrasonic nozzle. Thetwice-impregnated sorbent was then placed in an oven and dried byramping the oven temperature at 3° C./min to 150° C. and holding at 150°C. for 1 hour. The dried sorbent was then calcined by ramping the oventemperature at 3° C./min to 635° C. and holding at 635° C. for 1 hour.The resulting nickel-promoted sorbent was designated Sorbent C.

Sorbent D was prepared by mixing 20.0 grams of sodium pyrophosphate(available from Aldrich Chemical Company, Milwaukee, Wis.), 1690 gramsof deionized water, 200.0 grams of aluminum hydroxide powder (Dispal®Alumina Powder, CONDEA Vista Company, Houston, Tex.), 471 grams ofdiatomaceous earth (Celite® Filter Cell, available from Manville SalesCorporation, Lampoc, Calif.), 788 grams of zinc oxide powder (availablefrom Zinc Corporation, Monaca, Pa.), and 870 grams of sodium silicatesolution containing 9.1% Na₂O and 29.2% SiO₂ (available from BrainerdChemical Company, Tulsa, Okla.) to form a sorbent base slurry.

The sorbent base slurry was then formed into particulate using acounter-current spray drier (available from Niro Inc., Columbia, Md.).The sorbent base slurry was contacted in a particulating chamber withair flowing through the chamber. The air flowing through theparticulating chamber had an inlet temperature of about 320° C. and anoutlet temperature of about 145° C. The sorbent base particulate wasthen placed in an oven and dried by ramping the oven temperature at 3°C./min to 150° C. and holding at 150° C. for 1 hour. The dried sorbentbase particulate was then calcined by ramping the oven temperature at 5°C./min to 635° C. and holding at 635° C. for 1 hour.

A 100 gram quantity of the sorbent base particulate was then contactedwith sodium silicate by heating the particulate to 300° F. andcontacting it with a solution containing 40 ml of sodium silicate (9.1%Na₂O, 29.2% SiO₂, available from Brainerd Chemical Company, Tulsa,Okla.) and 10 ml of distilled water by spraying the solution on theparticulate with an ultrasonic nozzle. The coated sorbent baseparticulate was then placed in an oven and dried by ramping the oventemperature at 5° C./min to 120° C. and holding at 120° C. for 2 hours.The dried, coated particulate was then calcined by ramping the oventemperature at 5° C./min to 538° C. and holding at 538° C. for 1 hour.

The calcined, coated sorbent base particulate was then sieved to obtaina 100 gram quantity of coated sorbent base particulate which passedthrough the 100 mesh sieve but was retained above the 325 mesh sieve.

The 100 gram quantity of −100/+325 mesh particulate was then impregnatedwith a solution containing 74.28 grams of nickel nitrate hexahydrate and7 grams of distilled water by spraying the solution on the particulatewith an ultrasonic nozzle. The impregnated sorbent was then placed in anoven and dried by ramping the oven temperature at 3° C./min to 150° C.and holding at 150° C. for 1 hour. The dried sorbent was then calcinedby ramping the oven temperature at 5° C./min to 635° C. and holding at635° C. for 1 hour. The resulting sorbent was designated Sorbent D.

Sorbent E was prepared by impregnating 50 grams of Sorbent D with asolution containing 37.14 grams of nickel nitrate hexahydrate and 4grams of distilled water by spraying the solution on the sorbent with anultrasonic nozzle. The twice-impregnated sorbent was then placed in anoven and dried by ramping the oven temperature at 3° C./min to 150° C.and holding at 150° C. for 1 hour. The dried sorbent was then calcinedby ramping the oven temperature at 3° C./min to 635° C. and holding at635° C. for 1 hour the resulting sorbent was designated Sorbent E.

EXAMPLE II

The attrition resistance of Sorbents A-E was then determined using theDavison Test. The Davison Index, which represents the weight percent ofthe over 20 micrometer particle size fraction which is reduced toparticle sizes of less than 20 micrometers under test conditions, wasmeasured using a Jet cup attrition determination method. The Jet cupattrition determination involved screening a 5 gram sample of sorbent toremove particles in the 0 to 20 micrometer size range. The sorbentparticles above 20 micrometers were then subjected to a tangential jetof air at a rate of 21 liters per minute introduced through a 0.0625orifice fixed at the bottom of a specially designed Jet cup (1″ I.D.×2″height) for a period of 1 hour. The Davison Index (DI) was calculated asfollows:${DI} = {\frac{{{Wt}.\quad{of}}\quad 0{–20}\quad{Micrometer}\quad{Formed}\quad{During}\quad{Test}}{{{{Wt}.\quad{of}}\quad{Original}} + {20\quad{Micrometer}\quad{Fraction}\quad{Being}\quad{Tested}}} \times 100 \times {Correction}\quad{Factor}}$The correction factor of 0.3 was determined using a known calibrationstandard to adjust for differences in Jet cup dimensions and wear.

Table 1 summarizes the results of the Davison Tests on Sorbents A-E.TABLE 1 ATTRITION RESISTANCE TEST Sorbent Davison Index (%) A (Control-15% Ni Impregnated) 26.3 B (Control- 30% Ni Impregnated) 19.3 C(Na₂SiO₃— Mixed + 15% Ni Impregnated) 19.9 D (Na₂SiO₃— Mixed andSprayed + 4.8 15% Ni Impregnated) E (Na₂SiO₃— Mixed and Sprayed + 3.130% Ni Impregnated)

The results in Table 1 demonstrate that the presence of sodium silicatein and/or on a nickel-promoted sorbent enhances the attrition resistanceof the sorbent.

EXAMPLE III

Sorbents C-E were then reactor tested under desulfurization conditions.

A 10 gram quantity of −100/+325 mesh Sorbent C was placed in a reactor(1 inch I.D. fluidized bed reactor with clam shell heater) and heated to700° F. Catalytically Cracked Gasoline (CCG) (345 ppmw sulfur),nitrogen, and hydrogen were then simultaneously charged to the reactorat 13.4 ml/hr, 150 cc/min, and 150 cc/min, respectively. The reactor bedtemperature was maintained between about 730° F. and 740° F. Effluentsamples were taken at 4 hourly increments and designated Samples 1A-4A.

CCG flow to the reactor was then terminated and the sulfurized sorbentwas regenerated with air (60 cc/min) and nitrogen (240 cc/min) at atemperature of about 900° F. for about 100 minutes. The reactortemperature was then reduced to about 700° F. and the regeneratedsorbent was reduced with hydrogen (300 cc/min) for about 95 minutes. CCG(345 ppmw sulfur), nitrogen, and hydrogen were then simultaneouslycharged to the reactor at 13.4 ml/hr, 150 cc/min, and 150 cc/min,respectively. The reactor bed temperature was maintained between about730° F. and about 745° C. Effluent samples were taken at 4 hourlyincrements and designated Samples 1B-4B.

Samples 1A-4A (Cycle A) and 1B-4B (Cycle B) were analyzed for sulfurcontent using x-ray fluorescence. The results are summarized in Table 2.TABLE 2 Desulfurization of CCG (345 ppmw Sulfur) with Sorbent C SampleCycle A (ppmw Sulfur) Cycle B (ppmw Sulfur) 1 220 5 2 60 10 3 10 10 4 1015

A 10 gram quantity of −100/+325 mesh Sorbent D was placed in the reactorand heated to 700° F. CCG (345 ppmw sulfur) was then desulfurized in thereactor in substantially the same manner and under substantially thesame conditions as described with respect to Sorbent C. Effluent Sampleswere taken at 4 hourly increments and designated samples 1A-4A (CycleA).

The sulfurized sorbent was then regenerated and reduced in substantiallythe same manner as described with respect to Sorbent C. CCG was thendesulfurized as described in Cycle A. Effluent samples were taken athourly increments and designated 1B-4B (Cycle B).

The sulfurized sorbent was then regenerated and reduced in the samemanner as in Cycle B. CCG was then desulfurized in the same manner asCycle B. Effluent Samples were taken at hourly increments and designated1C-4C (Cycle C).

Samples from Cycles A-C were analyzed for sulfur content using x-rayfluorescence. The results are summarized in Table 3. TABLE 3Desulfurization of CCG (345 ppmw Sulfur) with Sorbent D Cycle A Cycle BCycle C Sample (ppmw Sulfur) (ppmw Sulfur) (ppmw Sulfur) 1 <5 <5 10 2 <55 15 3 15 5 45 4 15 20 110

A 10 gram quantity of −100/+325 mesh Sorbent E was placed in thereactor. CCG was desulfurized in the same manner as described withrespect to Sorbents C and D. Effluent samples were taken hourly anddesignated Samples 1A-4A (Cycle A).

The sulfurized sorbent was then regenerated in the same manner asSorbents C and D except the nitrogen flow rate was 180 cc/min and theair flow rate was 120 cc/min. The regenerated sorbent was reduced in thesame manner as Sorbents C and D.

Cycles B, C, D, and E were carried out in substantially the same manneras Cycle A, with regeneration and oxidation between each cycle beingaccomplished in the same manner as described above for regeneration andreduction between Cycle A and Cycle B.

Samples from Cycle A-E were analyzed for sulfur content using x-rayfluorescence. The results are summarized in Table 4. TABLE 4Desulfurization of CCG (345 ppmw Sulfur) with Sorbent E Cycle A Cycle BCycle C Cycle D Cycle E (ppmw (ppmw (ppmw (ppmw (ppmw Sample Sulfur)Sulfur) Sulfur) Sulfur) Sulfur) 1 10 <5 5 20 5 2 20 <5 10 25 15 3 20 510 45 95 4 30 10 — 110 185

Tables 2-4 demonstrate that a sorbent whose attrition resistance hasbeen enhanced with sodium silicate is effective to remove sulfur fromcracked-gasoline.

Reasonably variations, modifications, and adaptations can be made withinthe scope of this disclosure and the appended claims without departingfrom the scope of this invention.

1. A sorbent composition suitable for removing sulfur from ahydrocarbon-containing fluid, said sorbent composition comprising: asupport comprising zinc oxide, silica, and alumina; a promoter whereinsaid promoter comprises a reduced-valence promoter; and a silicate.
 2. Asorbent composition according to claim 1 wherein said promoter comprisesa metal selected from the group consisting of nickel, cobalt, iron,manganese, copper, zinc, molybdenum, tungsten, silver, tin, vanadium,antimony, and combinations thereof.
 3. A sorbent composition accordingto claim 1 wherein said silicate includes a metal component selectedfrom the group consisting of sodium, potassium, zirconium, aluminum,barium, beryllium, calcium, iron, magnesium, manganese, and combinationsthereof.
 4. A sorbent composition according to claim 1 wherein saidpromoter comprises reduced-valence nickel.
 5. A sorbent compositionaccording to claim 1 wherein said silicate is sodium silicate.
 6. Asorbent composition according to claim 1 wherein said sorbentcomposition comprises said zinc oxide in an amount in a range of fromabout 10 to about 90 weight percent, said silica in an amount in therange of from about 5 to about 85 weight percent, said alumina in anamount in the range of from about 1 to about 30 weight percent, saidreduced-valence nickel in an amount in the range of from about 0.5 toabout 50 weight percent, and said sodium silicate in an amount in therange of from about 1 to about 40 weight percent.
 7. A sorbentcomposition according to claim 1 wherein said reduced-valence nickel hasa valence of less than
 2. 8. A sorbent composition as claimed in claim 1wherein said promoter comprises at least 10 weight percentreduced-valence nickel, said reduced-valence nickel having a valence ofzero.
 9. A sorbent composition according to claim 1 wherein said sorbentcomposition comprises a microsphere having a mean particle size in therange of from about 1 micrometer to about 500 micrometers.
 10. A sorbentcomposition according to claim 1 wherein said sorbent composition has aDavison Index value of less than 20 percent.
 11. A process of making asorbent composition comprising: (a) admixing a first support componentand a second support component to form a support mix; (b) particulatingsaid support mix to thereby provide a support particulate; (c)contacting said support particulate with a promoter to thereby provide apromoted particulate comprising an unreduced promoter; (d) reducing saidpromoted particulate to thereby provide a reduced particulate comprisinga reduced-valence promoter; and (e) incorporating a silicate with asilicate-enhanced component selected from a group consisting of saidsupport mix, said support particulate, said promoted particulate, andcombinations thereof.
 12. A process according to claim 11 wherein saidsilicate includes a metal component selected from the group consistingof sodium, potassium, zirconium, aluminum, barium, beryllium, calcium,iron, magnesium, manganese, and combinations thereof.
 13. A processaccording to claim 11 wherein said promoter is selected from the groupconsisting of metals, metal oxides, and combinations thereof.
 14. Aprocess according to claim 11 wherein said first support componentcomprises zinc oxide.
 15. A process according to claim 11 wherein saidreduced-valence promoter has a valence which is less than the valence ofsaid unreduced promoter.
 16. A process according to claim 11 whereinsaid silicate-enhanced component is said support mix.
 17. A processaccording to claim 11 wherein said silicate is incorporated with saidsupport mix by physically mixing said silicate and said support mix. 18.A process according to claim 11 wherein said silicate-enhanced componentis said support particulate.
 19. A process according to claim 11 whereinsaid silicate is incorporated with said support particulate byimpregnating said support particulate with said silicate.
 20. A processaccording to claim 11 wherein said silicate-enhanced component is saidpromoted particulate.
 21. A process according to claim 11 wherein saidsilicate is incorporated with said promoted particulate by impregnatingsaid promoted particulate with said silicate.
 22. A process according toclaim 11 wherein said silicate comprises sodium silicate.
 23. A processaccording to claim 11 wherein said promoter comprises nickel.
 24. Aprocess according to claim 11 wherein said support mix comprises zincoxide, silica, and alumina.
 25. A process according to claim 11 whereinsaid reduced-valence promoter comprises reduced-valence nickel.
 26. Aprocess according to claim 25 wherein said reduced-valence nickel has avalence of less than
 2. 27. A process according to claim 25 wherein saidsupport mix is in the form of a slurry, wherein said slurry isparticulated by spray-drying, wherein said support particulate is in theform of a microsphere having a mean particle size in the range of fromabout 1 micrometer to about 500 micrometers.
 28. A process as claimed inclaim 25 wherein said silicate-enhanced component is said support mix.29. A process according to claim 25 wherein said silicate isincorporated with said support mix by physically mixing said silicateand said support mix.
 30. A process according to claim 25 wherein saidsilicate-enhanced component is said support particulate.
 31. A processaccording to claim 25 wherein said silicate is incorporated with saidsupport particulate by impregnating said support particulate with saidsilicate.
 32. A process according to claim 25 wherein saidsilicate-enhanced component is said promoted particulate.
 33. A processaccording to claim 25 wherein said silicate is incorporated with saidpromoted particulate by impregnating said promoted particulate with saidsilicate.
 34. A process according to claim 11 wherein said sorbentcomposition comprises zinc oxide in an amount in the range of from about10 to about 90 weight percent, silica in an amount in the range of fromabout 5 to about 85 weight percent, alumina in an amount in the range offrom about 1 to about 30 weight percent, reduced-valence nickel in anamount in the range of from about 0.5 to about 50 weight percent, andsodium silicate in an amount in the range of from about 1 to about 40weight percent.
 35. A process according to claim 34 wherein saidreduced-valence nickel has a valence of zero.
 36. A process according toclaim 34 wherein said support particulate is dried and calcined prior tocontacting with said promoter, and wherein said promoted particulate isdried and calcined prior to reduction.
 37. A process according to claim34 wherein said silicate-enhanced component is said support mix.
 38. Aprocess according to claim 34 wherein said silicate is incorporated withsaid support mix by physically mixing said sodium silicate, said zincoxide, said silica, and said alumina.
 39. A process according to claim34 wherein said silicate-enhanced component is said support particulate.40. A process according to claim 34 wherein said silicate isincorporated with said support particulate by spray-impregnating saidsupport particulate with said sodium silicate.
 41. A process accordingto claim 34 wherein said silicate-enhanced component is said promotedparticulate.
 42. A process according to claim 34 wherein said silicateis incorporated with said promoted particulate by spray-impregnatingsaid promoted particulate with said sodium silicate.
 43. The productproduced by the process of claim
 11. 44. The product produced by theprocess of claim
 31. 45. A process for removing sulfur from ahydrocarbon-containing fluid stream, said process comprising the stepsof: (a) contacting said hydrocarbon-containing fluid stream with asorbent composition comprising a support, a promoter, and a silicate ina desulfurization zone under conditions such that there is formed adesulfurized fluid stream and a sulfurized sorbent; (b) separating saiddesulfurized fluid stream from said sulfurized sorbent; (c) regeneratingat least a portion of the separated sulfurized sorbent in a regenerationzone so as to remove at least a portion of the sulfur therefrom andprovide a desulfurized sorbent; (d) reducing said desulfurized sorbentin an activation zone to provide a reduced sorbent composition whichwill affect the removal of sulfur from said hydrocarbon-containing fluidstream when contacted with the sane; and (e) returning at least aportion of said reduced sorbent composition to said desulfurizationzone.
 46. A process in accordance with claim 45 wherein said supportcomprises zinc oxide, silica, and alumina.
 47. A process in accordancewith claim 46 wherein said promoter comprises nickel.
 48. A process inaccordance with claim 47 wherein said silicate comprises sodiumsilicate.
 49. A process in accordance with claim 45 wherein saidcontacting is carried out at a temperature in the range of from about100° F. to about 1000° F. and a pressure in the range of from about 15to about 1500 psia.
 50. A process in accordance with claim 45 whereinsaid regeneration is carried out at a temperature in the range of fromabout 100° F. to about 1500° F. and a pressure in the range of fromabout 25 to about 500 psia.
 51. A process in accordance with claim 50wherein there is employed air as a regeneration agent in saidregeneration zone.
 52. A process in accordance with claim 45 whereinsaid desulfurized sorbent is subjected to reduction with hydrogen insaid activation zone which is maintained at a temperature in the rangeof from about 100 EF to about 1500 EF and a pressure in the range offrom about 15 to about 1500 psia during reduction.
 53. A process inaccordance with claim 45 wherein the separated sulfurized sorbent isstripped prior to introduction into said regeneration zone.
 54. Aprocess according to claim 45 wherein said desulfurized sorbent isstripped prior to introduction into said activation zone.
 55. A processin accordance with claim 45 wherein said promoter comprisesreduced-valence nickel having a valence of less than
 2. 56. A process inaccordance with claim 45 wherein said promoter comprises reduced-valencenickel having a valence of zero.
 57. A process in accordance with claim45 wherein said hydrocarbon-containing fluid stream is cracked-gasoline.58. A process in accordance with claim 45 wherein saidhydrocarbon-containing fluid stream is diesel.
 59. The product producedby the process of claim
 57. 60. The product produced by the process ofclaim 58.